I'd agree that, in general, it is a good website for booking. However, the change in IT systems has not been smooth with slipping go-live dates and a number of issues which affect the customers; unable to login, error messages for those that manage to log in, a number of people were classified as under 18, and so on. Plus giving targets for fixes which haven't been met.
For example I am still unable to log in to manage my booking (book seats, print tickets etc).
The main grumble from the customers has been lack of information about the problems. It took 3 days for them to place a message on the login screen explaining that there were continuing problems logging in. The result is a lot of upset customers.